Solvent Effects on the UV–Vis Absorption Properties and Tautomerism of N-Confused Tetraphenylporphyrin

Abstract

The two tautomeric forms of N-confused tetraphenylporphyrin (NCTPP) show distinctly different absorption spectra. The existence of each tautomer in solution has been shown to be strongly solvent-dependent. In the present work, we have studied the tautomerization using absorption spectroscopy in 15 different solvents. While changes in the two tautomers are not large in the Soret band region, the distinct spectral changes between the two tautomers in the Q-band region provide a convenient way to measure the concentration of each tautomer. The resulting data shows a strong correlation between the tautomer and the H-bond accepting ability of the solvent. The anomaly in this data is for the alcoholic solvents ethanol and methanol, for which we observe evidence for H-bonding, presumably between the exterior N2 nitrogen of the NCTPP and the O-H proton of the solvent.

Bicyclic Phenyl–Ethynyl Architectures: Synthesis of a 1,4‐Bis(phenylbuta‐1,3‐diyn‐1‐yl) Benzene Banister

“…Fortunately, UV/VIS spectra recorded in CH 2 Cl 2 and CHCl 3 should at least be qualitatively comparable [37] . As expected, the extended conjugated π‐system in the banister of 1 is reflected in a large bathochromic shift compared to 2 .…”

Chirogenesis in Zinc Porphyrins: Theoretical Evaluation of Electronic Transitions, Controlling Structural Factors and Axial Ligation

“…Synthetic porphyrins also found a broad application in catalysis, [4–6] optical and chemo sensors, [7–15] light harvesting, [5,16–18] medicine, [19–22] supramolecular systems, [1,23–27] electronic devices, [11,28,29] etc. Specific natural and supramolecular chiral environment may result in chirogenic processes in porphyrin chromophores, which can be detected by various spectroscopic methods such as X‐ray, [30–33] IR, [31,34] Raman, [32] NMR, [31,32,35,36] circular polarized luminescence, [30,37,38] vibrational, [34,39,40] electronic (ECD), [9,19,41–44] and magnetic [34,45,46] circular dichroism.…”

Simple 3,6‐disubstituted Carbazoles as Potential Hole Transport Materials: Photophysical, Electrochemical and Theoretical Studies

“…The largest blue‐shift is observed for THF and toluene (4 and 3 nm, respectively, for CZ 1 , and 7 and 4 nm, respectively, for CZ 2 ). Such behavior is characteristic of the donor‐acceptor conjugated systems (54). Further, they display a slight bathochromic shift in polar solvents such as DMF and acetonitrile when compared to CHCl 3 .…”